Basis for original (SCP) IDLH: The chosen IDLH is based on the statement by ACGIH [1971] that 0 of 6 rats died from a 4-hour exposure to 4,000 ppm and 6 of 6 rats died after a 4-hour exposure to 8,000 ppm [Smyth et al. 1951]. No other quantitative data are available on which to base the IDLH.

Short-term exposure guidelines: None developed

ACUTE TOXICITY DATA:

Lethal concentration data:

Species

Reference

LC50(ppm)

LCLo(ppm)

Time

Adjusted 0.5-hrLC (CF)

Derived value

Rat

NCI 1974

4,000

—–

4 hr

8,000 ppm (2.0)

800 ppm

Mouse

Shell 1961

—–

7,000

40 min

7,630 ppm (1.09)

763 ppm

Rat

Smyth et al. 1951

LC100: 8,000

—–

4 hr

16,000 ppm (2.0)

1,600 ppm

Other animal data: It has been reported that rats have survived an exposure to 4,000 ppm for 4 hours [Smyth et al. 1951].

Human data: Volunteers have complained of nose and throat irritation after brief exposures to concentrations ranging from 10 to 20 ppm [Amoore and Hautala 1983].

Revised IDLH: 750 ppmBasis for revised IDLH: The revised IDLH for isopropylamine is 750 ppm based on acute inhalation toxicity data in animals [NCI 1974; Shell 1961]. This may be a conservative value due to the lack of relevant acute toxicity data for workers exposed to concentrations above 20 ppm.